MediaSet: Send creation event only when the object created
MediaSet: Send creation event only when the object created

Change-Id: I9054958cf6f545502447352ff71856e0477609b3

Kurento/kms-core,ESTOS/kms-core,shelsonjava/kms-core,ESTOS/kms-core,TribeMedia/kms-core,TribeMedia/kms-core,shelsonjava/kms-core,shelsonjava/kms-core,ESTOS/kms-core,TribeMedia/kms-core,Kurento/kms-core,shelsonjava/kms-core,Kurento/kms-core,ESTOS/kms-core,Kurento/kms-core,TribeMedia/kms-core